Not sure what you mean by a new league. But resetting your team in 'edit team' will allow you to start over.Using another profile on your console will allow you to have two teams.

A good tip is to not solely look at overall rating when purchasing players. Look at their attributes for the position you're looking to buy. That way you'll save a bit of cash to build a more well rounded team.

2) Despite setting it to search for players at your level. Some people only invest in 2-3 very good players, they'll still be at your level because they only improved in 2 or so positions while selling 7+ players.

I only set my search to team strength. Don't really care what their personal rating or pass assistance is like.